Thoreau Center for Sustainability—a network of nonprofit groups concerned with green design and sustainability in real estate ventures.(Leddy Maytum Stacy Architects)

Location: San Francisco
Built: 1899 to 1933
Renovated: 1996
Architect: Leddy Maytum
Stacy Architects
LEED Rating: None

BY STEPHANIE JOY SMITH

In 1776, the Spanish Empire established the Presidio, an outpost commanding strategically important views of what is now San Francisco Bay. The site was later controlled by Mexico before the U.S. Army took over in 1846. It eventually became the Army's Western Defense Command Headquarters and grew to include some 500 buildings. In 1994, the Army handed the Presidio over to the National Park Service, and the site officially became part of the Golden Gate National Recreation Area.

Over the years, the Presidio had deteriorated, and the Park Service was faced with the prospect of revitalizing more than 500 historic buildings. The first structures to get major attention were the seven buildings making up the Letterman Hospital complex. The buildings were converted into office space for the Thoreau Center for Sustainability, a network of nonprofit groups concerned with green design and sustainability in real estate ventures. Naturally, the project was bound to go green.

Project architect Marsha Maytum says that the hospital's buildings had originally been designed to take advantage of the area's mild climate, with operable windows that let in plenty of natural light and fresh air. The architects made use of these qualities, and the result was an open floor plan with glass partitions. Sustainably harvested wood, cotton insulation, formaldehyde-free paints, and recycled materials—including tiles made from automobile and airplane windshields—added less than one percent to the cost of the project.

"A green building does not have to cost more," Maytum says.

The project was completed in 1996, before the LEED certification process had been finalized, but it was used as a prototype to test LEED standards and has served as a model for sustainable design in preservation, not just in California but also around the world.

For more of this article, look for the January/February 2008 issue on newsstands or e-mail us to purchase a copy. Subscribe to the magazine.